BIO 311D 2nd Edition Lecture 40 Outline of Last Lecture I Energy flow and trophic structure How does this affect human k II Nutrient cycling and eutrophication III In class exercise and course instructor survey Outline of Current Lecture I Effects of human activity on ecosystems II Conservation biology efforts III Index Card Questions Current Lecture I Effects of human activity on ecosystems A Carbon Cycle a Producers use CO2 during photosynthesis producing organic compounds b All organisms release CO2 in cellular respiration c Two ways we re affecting the cycle burning fossil fuels deforestation B Nitrogen Cycle a Nitrogen fixation b What are some humans are messing with the nitrogen cycle Pollution a lot of bare dirt alters water availability increase surface runoff add fertilizer less likely to runoff c More fertilizer and fixed nitrogen leads to more runoff C Eutrophication a Over production of the organism Crystal clear lake murky green lake b Dead zone dangerously low dissolved oxygen everyone is going over their K 1 Around the Gulf of Mexico many dead zones fish can t live here Runoff from the center of the entire U S from the Mississippi river D Biodiversity a Habitat loss or habitat degradation 1 Habitat destruction and habitat fragmentation isolated patches support less biodiversity 2 Large patch the edge effect the inner area is not influenced by edge effects 3 Smaller patch the width of the edges is relatively constant as the total area becomes smaller the edge becomes proportionately larger 4 Could lessen the edge effects by attaching habitats corridors b Spread of invasive species 1 Introduced species no natural enemies and parasites so out compete native species 2 Imported parasites from initial habitat reintroduce natural parasites c Over harvesting and over exploitation 1 How are humans directly affecting populations of fish shrimp and elephants Over fishing fish shrimp new fishing regulations Elephants taking the tusks to sell as ivory 2 Indirect effects of over fishing over harvesting why are killer whales eating more sea otters now We re devastating the fish population that feeds the whale population so they are now feeding on sea otters E Fire ecology in Yellowstone National Park and in Bastrop Texas How does human activity affect this a Leading to huge natural disastrous fires when we try to mess around with natural processes F Global Amphibian Decline a Global climate change II Conversation Biology Effects A How should we define biodiversity for conservation purposes a Genetic variation b Species diversity c Ecosystem diversity B What are ecosystem services a Provide freshwater b Reducing air pollution C Reducing population genetics to ecology a What are some normal sources of genetic variability in sexually reproducing organisms independent assortment crossing over b How can random evens such as genetic bottlenecking affect genetic variability It lessens it D Relating ecology to genetics and evolution a Modern agricultural practices tend to favor monocultures with low genetic variance b What happens when a parasite enters E Loss of genetic variability and small population size interact to contribute to extinction F Species level legislation Federal a World Wildlife Fun World Wide Fund for Nature world s largest conservation non governmental organization NGO by membership initially focused on endangered species but mission has expanded G Ecosystem or Ecosystem Based Management H Land use and conservation in Costa Rica a Attention to biodiversity hot spots habitat corridors b Effects of ecotourism carbon credits agricultural practices community involvement
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